Exchangeable bearers for a convertible offset press



March 9, 1965 H. R. DICKERSON 3,172,359

EXCHANGEABLE BEARERS FOR A CONVERTIBLE OFFSET PRESS Filed Aug. 8, 1963 INVENTOR HENRY R- D/C'KEQSON ATTOENEVS United States Patent C) 3,172,359 EXCHANGEABLE BEARERS FOR A CON- VERTIBLE OFFSET PRESS Henry R. Dickerson, 3414 Grace Road, Kalamazoo Township, Kalamazoo County, Mich.

Filed Aug. 8, 1963, Ser. No. 390,890 6 Claims. (Cl. 101-142) This invention relates in general to a combination letter press and offset press and, more particularly, to a mechanism and method for converting a rotary offset press into a letter press which can be reconverted into an offset press.

Persons familiar with the use and operation of rotary printing equipment have long accepted as fact the theory that offset or lithographic printing requires one machine and letter press or letter set printing requires another machine. Accordingly, and for a great many years, printing firms have been obliged to purchase two machines in order to produce both offset and letterpress printing. Sometimes because of personal preference and sometimes as the result of cost, time or other considerations, lithographic or offset printing is preferred over letterpress, and vice versa. However, since printing machines of this type are very expensive, many small operators are obliged either to incur a large indebtedness, in order to have machines of both types, or to turn down a substantial amount of business for the lack of one of the two types of machines. Moreover, even in large printing plants, there are often periods in which the demand is much greater for one type of printing than for the other so that one type of press may be idle while the other type is being operated around the clock.

Accordingly, the object and purposes of this invention have been to provide:

(1) A combination rotary printing press capable of being operated either as a letter press or as an offset press and which will produce high quality printed material of either type;

(2) A combination rotary printing press, as aforesaid, which is basically an offset printing press but which can be modified by the apparatus and method of my invention so that it can be quickly converted into a letterpress and, just as quickly, reconverted into an offset press, the down time for such conversion being not materially in excess of the normal time required to set up the machine for a printing operation of either type;

(3) A method for converting an offset press into a letter press, which method can be easily carried out by any press operator capable of setting up the press for operation and thereafter operating same;

(4) A mechanism for converting an offset press into a letter press which is extremely accurate in its performance and which requires little or no additional main-tenance as a result of such conversion, said mechanism being relatively inexpensive to produce and install, and being adaptable for use on any of the conventional offset presses presently in general use.

Other objects and purposes of this invention will become apparent to persons familiar wit-h this type of equipment upon reading the following descriptive material and examining the accompanying drawings, in which:

FIGURE 1 is a broken side elevational View, taken substantially along the line II of FIGURE 2, of a portion of an oftset printing press capable of embodying the mechanism of the invention and upon which the method of the invention may be performed.

FIGURE 2 is a sectional view substantially as taken along the line IIII in FIGURE 1 and rotated approximately 90 degrees clockwise.

FIGURE 3 is a fragment of FIGURE 1 disclosing a patented Mar. 9, 1965 portion of the press after it has been modified according to the teachings of the invention.

FIGURE 4 is a sectional view taken along the line IVIV in FIGURE 3.

FIGURE 5 is an exploded, side elevational view of a cylinder bearer according to the invention.

FIGURE 6 is a fragmentary and partially exploded, sectional view substantially as taken along the line VI VI in FIGURE 4.

For convenience in description, the terms upper, lower and words of similar import will have reference to the printing press and parts associated therewith as appearing in FIGURE 1. The terms front, or feeder end and rear or delivery end will have reference, respectively, to the right and left ends of the machine appearing in FIGURE 1. The terms inner, outer and derivatives thereof will have reference to the geometric center of said machine and parts thereof pertinent to the invention.

In general The objects and purposes of the invention, including, those set forth above, have been met by modifying a rotary offset or lithographic printing press so that it can be used as either an offset press or a letter press by a simple exchange of parts. More specifically, the bearers furnished with the impression cylinder are removed from the axial ends of the impression cylinder. The impression cylinder is then equipped with a pair of modified bearers which can be removed from the impression cylinder quickly and easily without removing the cylinder from the machine. When the convertible press is to be used for offset printing, the bearers will be of diameter slightly less than the diameter of the impression cylinder (as in existing offset presses) and, in all other respects, the structure and operation of the offset press will be exactly as though the machine had not been modified. However, when the convertible press is being used to run letterpress, the blanket is removed from the blanket cylinder and placed on the plate cylinder, and the printing plate is mounted on the blanket cylinder. The undersized bearers are removed from the impression cylinder and replaced with a pair of larger bearers, which peripherally engage the bearers on the blanket cylinder. Except for minor adjustments, the erstwhile lithographic printing press is now ready to produce letterpress.

Detailed description The method of the invention, whereby an offset printing press can be converted to produce letterpress, is more readily disclosed by describing the mechanism which is used to modify the offset press so that the conversion from one type of use to the other can be effected quickly, easily and in a manner to produce high quality printing, whether the printing machine is to be used for letterpress or offset printing. Accordingly, the following description is intended to disclose briefly a substantially conventional offset press 10 (FIGURE 1) and the mechanism by which it is modified into a convertible press upon which the method of the invention can be practiced.

Offset presses, one of which is shown in part at 16 in FIGURE 1, are well known and widely used in the printing trade. One example of an existing offset or lithographic press is identified as the Miehle model 43/60 offset press manufactured by The Miehle Company, Division of Miehle-Goss-Dexter, Inc., Chicago 8, Illinois, and illustrated in their bulletin No. 5 MOP861. Another example of an existing offset press is identified as the Miller SI23x36 which is produced by the Miller Printing Machinery Company located at 1105 Reedsdale Street, Pittsburgh, Pennsylvania. For purposes of comparison, the Miller Printing Machinery Company also manufactures a letter press identified as model No.

SY27x4l. The general construction of rotary letter presses is Well known so that a description thereof is believed to be unnecessary in this application.

Briefly, the offset press of FIGURE 1, which is described for illustrative purposes, includes a frame structure 11 upon which the plate cylinder 12, the blanket cylinder 13 and the impression cylinder 14 are rotatably mounted in axially parallel positions by means of the shafts 16, 17 and 18, respectively, in a substantially conventional manner. That is, the blanket cylinder 13 is nearly directly below the plate cylinder 12, and is slightly higher than the impression cylinder 14. A plurality, here three, of delivery cylinders 21 are mounted by means of shafts 22 upon the frame structure 11 below the level of the blanket cylinder 13 and impression cylinder 14. A feeder ramp 23 is disposed near the front of the frame structure 11 for the purpose of advancing sheets 24 of material, such as paper stock, to the impression cylinder 14 so that each sheet is moved, one at a time, between the impression cylinder 14 and the blanket cylinder 13 to effect printing of said sheets. Various guides and transfer devices indicated generally at 26, are provided at the lower end of the feeder ramp 23 for the purpose of guiding and transferring each sheet from the ramp 23 onto the impression cylinder 14 in a conventional manner.

A plurality of inking rollers, indicated gene-rally at 27 (FIGURE 1), are rotatably supported in a substantially conventional manner upon the upper end of the frame structure 11 directly above the plate cylinder 12 so that at least some of said inking rollers 27 are in circumferential engagement with the plate cylinder 12. Since the machine being described is an oifset press, it also has a plurality of water rollers 28 which are supported upon the frame structure 11 so that at least some thereof engage the plate cylinder 12in advance of the points at which the inking rollers 27 engage said plate cylinder. The plate cylinder 12, blanket cylinder 13, impression cylinder 14 and delivery cylinder 21 are all driven by appropriate gear means, not shown, in a substantially conventional manner so that they rotate at substantially the same angular speeds. The plate cylinder 12, blanket cylinder 13 and impression cylinder 14 have approximately the same outside diameter so that they rotate at approximately the same peripheral speeds.

The plate cylinder 12 (FIGURE 1) and blanket cylinder 13 have fiat, annular bearers at both axial ends thereof, two of such bearers being shown at 31 and 32 on the cylinders 12 and 13, respectively. The bearers 31 and 32, as well as their counterparts at the opposite ends of the plate cylinder 12 and blanket cylinder 13 are in continuous peripheral engagement and they are identical in diameter. However, and as shown in FIGURE 2, the bearers 32 and 32a on the blanket cylinder 13 are not in peripheral engagement with the bearers 33 and 330, respectively, on the opposite ends of the impression cylinder 14. Engagement is not necessary between the bearers on the blanket cylinder 13 and impression cylinder 14 because the blanket 36 on the blanket cylinder 13 serves to prevent slippage between the two cylinders and resultant slurring of the printing. The need for hav ing firm bearer contact between the plate cylinder 12 and blanket cylinder 13 and the lack of such need for firm bearer contact between the blanket cylinder 13 and the impression cylinder 14 is well known in the art.

The blanket 36 (FIGURE 1) is held on the blanket cylinder 13 by blanket clamps 37, and the printing plate 38 'is held on the plate cylinder 12 by the plate clamps 39. The blanket clamps 37 and plate clamps 39 may be of any conventional type. The impression cylinder 14 is provided with a sheet edge gripper 42 which may also be of a substantially conventional type for engaging the leading end of a sheet 24.

The foregoing descriptive material discloses briefly the parts of a substantially conventional offset press, of the type presently used, which parts are or may be operably associated with the modification mechanism whereby the offset press 10 becomes a convertible press and the method of the invention can be carried out. The olfset press 10 is prepared for use in practicing the method of the invention by removing the bearers 33 and 33a from the opposite ends of the impression cylinder 14. This may require the removal of the impression cylinder 14 from its position of support upon the frame structure 11. When the cylinder 14 is in its normal position on the frame structure 11 without the bearers 33 and 3311, said cylinder 14 is closely adjacent the blanket cylinder 13, the rearward end of the feeder ramp 23 and the forwardmost of the delivery cylinders 21.

A pair of adjustable bearers 43 and 44 (FIGURE 4) can now be mounted upon the opposite ends of the impression cylinder 14. More specifically, the adjustable bearer 43, for example (FIGURES 4, 5 and 6) is comprised of an inner annular member 46 and an outer annular member 47, which is capable of snugly embracing and encircling the inner member 46. The inner member 46 has a central opening 48 which preferably snugly embraces the shaft 18. The inner member 46, which is relatively flat and very sturdy, is preferably fabricated from a very durable material, such as steel. Said inner member 46 consists of two similar, substantially semicircular elements 51 and 52 having interfitting teeth 53 and 54, respectively, along their engaging, substantially diametrical edges. Each of the semicircular elements 51 and 52 has a plurality of screw openings 56 (FIGURE 5) into which the screws 57 (FIGURE 6) are slidably received for threaded engagement with the threaded openings 58 in the adjacent end of the impression cylinder 14. When the semicircular elements 51 and 52 are thus mounted upon the impression cylinder 14, the outer per pheral surface of the inner member 46 is concentric with the shaft 18.

The outer annular member 47 (FIGURE 5), which is preferably fabricated from steel, has two semicircular elements 61 and 62 having interfitting teeth 63 and 64 on their adjacent ends. When said teeth 53, 54 and 63, 64 of the members 46 and 47, respectively, are in their engaged positions (FIGURE 6), the inside diameter of the outer member 47 substantially identical with the outside diameter of the inner member 46. Each of the semicircular elements 61 and 62 has a plurality of radial screw openings 66 through which the screws 67 (FIG- URE 5) are sildably received for threaded reception into threaded openings 68 in the peripheral surface of the inner member 46.

The removable bearer 44 has a two-piece inner annular member 71 and a two-piece outer annular member 72 (FIGURE 4) which may be, and preferably are, identical in size, shape and all other respects with the corresponding parts of the inner member 46 and outer member 47, respectively, of the bearer 43. In fact, the outside diameter of the outer annular members 47 and 72 are preferably identical.

For reasons appearing hereinafter, each offset press 10, which is modified according to my invention, is advantageously provided with several pairs of removable bearers 43 and 44 having slightly different outside diameters. Thus, if it becomes desirable to use the press 10 as an offset press, after it has been modified into a convertible press 10a (FIGURE 3), as set forth above, a pair of removable bearers, similar to those shown at 43 and 44 (FIGURE 4), but having outside diameters slightly less than the outside diameter of the impression cylinder 14 can be mounted upon the impression cylinder. Under normal circumstances the diameter of the removable bearers 43 and 44 will be approximately 15 thousandths of an inch smaller than the diameter of the impression cylinder 14 when offset printing is to be performed by the modified press 10a. It follows, of course, that the plate cylinder 12, the blanket cylinder 13 and other parts of the offset press 10 may be used in their usual, conventional form when the press is used as an ofiset press.

When it becomes desirable to use the modified offset press a (FIGURE 3) to perform as a letter press, the small removable bearers 43 and 44 are removed from the opposite ends of the impression cylinder 14 and replaced with removable bearers having a large diameter. Under normal circumstances, the outside diameter of the replacement bearers 43 and 44 will be equal to the diameter of the impression cylinder 14 plus the thickness of the paper stock to be printed. The diameter of the impression cylinder 14 plus the thickness of the paper stock 24 can exceed by approximately three thousandths of an inch the diameter of the bearers 43 and 44 without adversely affecting the operation of the press. However, substantially identical diameters are preferred.

It will follow from the foregoing that substantial variations in paper stock will necessitate variations in the outside diameter of the removable bearers 43 and 44. Where the variations are relatively small, they can be accommodated by changing the outer members 47 and 72 only. In critical ranges of paper stock variation, it is advisable to have a plurality of outer members 47 and 72 which differ in outside diameter by relatively small increments, such as two thousandths of an inch. On the other hand, by properly building up the diameter of the impression cylinder, in a well-known manner, the number of removable bearers, or outer members thereof, can be reduced.

After the proper bearers 43 and 44 have been mounted upon the im pression cylinder 14, the blanket 36 and blanket clamps 37 are removed from the blanket cylinder 13 and replaced by the printing plate 38 and plate clamps 39. The clamps 37 and 39 may require minor modifications to permit this exchange. Alternatively, the blanket clamps 37 may be modified so that they can hold either the plate or the blanket, just as some existing plate clamps presently can. The blanket cylinder 13 is usually about 75 thousandths of an inch smaller than the diameter of the bearers 32 and 32a (FIGURES 2 and 4) on the blanket cylinder 13. Thus, since the printing plate 38 is only approximately 30 thousandths of an inch thick, the blanket cylinder 13 must be built up with packing so that the total diameter of the blanket cylinder 13 with the packing and printing plate thereon will be substantially identical with the diameters of the bearers 32 and 32a.

Due to the packing under the plate 38 (FIGURE 4), the printing plate will be able to move slightly radially inwardly with respect to the blanket cylinder 13 upon which it is mounted. Thus, crushing of the printing plate 38 may be avoided in the event that something, such as a corner of the sheet being printed, passes with the sheet between the printing plate on the cylinder 13 and the impression cylinder 14.

The blanket 36 and blanket clamps 37 are mounted upon the plate cylinder 12 so that it merely acts as another inking roll. It has been found that the firm contact between the bearers 32 and 32a on the cylinder 13 and the removable bearers 43 and 44 on the impression cylinder 14, when the modified press 10a (FIGURE 3) is used as a letterpress, cause the press to produce high quality letterpress printing on a machine which is basically an offset press.

When it becomes desirable to again use the modified press 10a as an offset press, the printing plate 38 is removed from the blanket cylinder and replaced by the blanket 36. The smaller removable bearers 43 and 44 are mounted upon the impression cylinder 14 and an offset printing plate is mounted upon the plate cylinder 12. The modified press 10a is now ready for operation as an offset press.

It will be seen that the removable bearers 43 and 44, being split, can be removed easily and quickly from the impression cylinder 14 and replaced with another set of removable bearers 43 and 44 of a diflerent size.

Although the foregoing description discloses a preferred embodiment of an apparatus including the mechanism of the invention, and capable of carrying out the method of the invention, will be understood that variations or modifications of such descriptive material, which come within the scope of the appended claims are fully contemplated.

What is claimed is:

1. An apparatus for modifying a rotary offset press, having a blanket cylinder, a plate cylinder and an impression cylinder, said blanket cylinder having a pair of circular bearers rigidly secured to the opposite ends of said blanket cylinder and being of substantially the same diameter as said blanket cylinder, the combination comprising:

a pair of inner annular members rigidly secured to the opposite axial ends of the impression cylinder in radial and respective alignment with the bearers on said blanket cylinder, each inner member being comprised of a pair of substantially semicircular elements having cooperating means thereon for positioning said elements together to form a ring of smaller diameter than said impression cylinder;

a pair of outer annular members of substantially the same external diameter as the diameter of said bearers, each outer member being comprised of two substantially semicircular parts and cooperating means for releasably holding said parts together snugly around one of said inner members; and

means for rigidly and releasably securing said outer members around and upon said inner members and concentric therewith, said outer members being adapted for peripheral engagement with said bearers.

2. The structure of claim 1 wherein the diameter of said bearers is greater than the diameter of the blanket cylinder by an amount not significantly less than the thickness of a printing plate mounted upon said blanket cylinder and wherein the outside diameter of each of the outer members on the impression cylinder is approximately equal to the diameter of the impression cylinder plus twice the thickness of the paper stock which is passed between the blanket cylinder and the impression cylinder.

3. The structure of claim 1 wherein both pairs of inner and outer annular members are comprised of a pair of semicircular elements having interfit-ting teeth on their opposing ends which, when interfitted, hold said members in a position wherein their radially inner and outer surfaces define circles, said circles being concentric when said inner and outer members are mounted upon the ends of the impression cylinder.

4. The structure of claim 1, including a plurality of pairs of outer annular members of slightly difierent external diameters ranging from slightly smaller than the diameter of said impression cylinder to slightly larger than the diameter of the impression cylinder, the internal diameters of said pairs of outer annular members being the same whereby said pairs of outer annular members may be alternatively mounted on said inner annular members for peripheral engagement with said bearers.

5. An apparatus for modifying a rotary offset press, having a blanket cylinder, a plate cylinder and an impression cylinder, said blanket cylinder having a pair of circular bearers secured to the opposite ends thereof and being of substantially the same diameter as said blanket cylinder, the combination comprising:

a pair of inner annular member rigidly secured to the opposite axial ends of the impression cylinder in radial and respective alignment with the bearers on said blanket cylinder, each inner member being com prised of a pair of arcuate elements having cooperating means thereon for positioning said arcuate elements together to form a ring of smaller outside diameter than said impression cylinder;

a pair of outer annular members of substantially the '5 8 same external diameter as the diameter of said bearmounting a curved printing plate on the blanket cylers, each outer member being comprised of two arcuinder; ate parts and cooperating means for releasably holdcausing the clamps on said blanket cylinder to receive ing said parts together snugly upon one of said inner and hold said printing plate; members; and 5 removing the bearers from the impression cylinder; means for rigidly and releasably securing said outer mounting on the opposite ends of said impression cylrnembers upon said inner members and concentric inder a pair of split annular members of smaller therewith, said outer members being adapted for diameter than said impression cylinder; and peripheral engagement with said bearers. mounting concentrically upon said annular members 6. In a method for converting into a letter press a 10 a pair of split annular bearers of larger diameter rotary offset press having a frame structure supporting than said impression cylinder,- said split annular bear: a plate cylinder and clamp means for holding a plate ers being of substantially the same diameter as, and thereon, a blanket cylinder and clamp means for holding engageable respectively with, the bearers on the a blanket thereon and an impression cylinder, each of said blanket cylinder, said annular bearers being mounted cylinders having bearers at the opposite ends thereof, the 15 upon said annular members while said impression bearers on the impression cylinder being of smaller diamcylinder is in operating position on the frame struceter than the diameter of the impression cylinder and the ture. bearers on the blanket cylinder being of about the same diameter as the diameter of the blanket cylinder With the References Cited m the file of this patent blanket thereon, the steps comprising: 20 UNITED STATES PATENTS removing the blanket from the blanket cylinder and in- 2,270,272 Davidson Jam 20, 1942 stalling said blanket on the plate cylinder; 2,853,003 Kaldschmidt et al Sept. 23, 1958 

1. AN APPARATUS FOR MODIFYING A ROTARY OFFSET PRESSHAVING A BLANKET CYLINDER, A PLATE CYLINDER AND AN IMPRESSION CYLINDER, SIAD BLANKET CYLINDER HAVING A PAIR OF CIRCULAR BEARERS RIGIDLY SECURED TO THE OPPOSITE ENDS OF SAID BLANKET CYLINDER AND BEING OF SUBSTANTIALLY THE SAME DIAMETER AS SAID BLANKET CYLINDER, THE COMBINATION COMPRISING: A PAIR OF INNER ANNULAR MEMBER RIGIDLY SECURED TO THE OPPOSITE AXIAL OF THE IMPRESSION CYLINDER IN RADIAL AND RESPECTIVE ALIGNMENT WITH THE BEARERS ON SAID BLANKET CYLINDER, EACH INNER MEMBER BEING COMPRISED OF A PAIR OF SUBSTANTIALLY SEMICIRCULAR ELEMENTS HAVING COOPERATING MEANS THEREON FOR POSITIONING SAID ELEMENTS TOGETHER TO FORM A RING OF SMALLER DIAMETER THAN THE SAID IMPRESSION CYLINDER; 